The present invention pertains to a safety ski binding of a type shown in EP 0091574B1, which discloses a safety ski binding having a first jaw unit (a so called "sensing unit") which cannot be released. The first jaw unit is provided with two soleholders which engage the sole of a ski boot from above and from lateral respective sides. These soleholders are mounted on a common pin which permits a slight lateral pivotal movement. A bearing member which carries such pin also permits slight pivotal movement about a horizontal transverse axle which is mounted in a housing that is secured to the ski. Contact switches, which are actuated when such pivot movements reach predetermined values, are provided and are comprised of three pressure pickups which are installed within the housing. Such a design permits the detection of forces which occur adjacent to the sensing jaw unit. Whereas such a ski binding had certain advantages over other known safety ski bindings, it has met with limited acceptance probably due to the fact that the sensing jaw is relatively complex and involves a high structural expenditure. In this respect, the disclosed device includes pressure-applying pistons and pressure pickups which inherently include sealing problems.
It an object of the present invention to provide a safety ski binding which is of a type as heretofore described, but which is designed such that it can be manufactured in a simple manner, at a lower cost and with less susceptibility to malfunction.
In accordance with the present invention there is provided a sensing unit for use with a releasable safety ski binding for retaining a ski boot on a ski. The binding includes a base plate attachable to the ski having an axle mounted thereon. The axle is transverse to the axis of the ski and parallel to the surface thereof. A cam surface is associated with the axle and a ski boot holder is mounted on the axle for rotational and axial movement thereon. The boot holder is dimensioned to hold a ski boot laterally and from above and has a boot holding position and a boot release position. First spring means are provided to bias the boot holder into rotation about the axle toward the boot holding position. Second spring means are provided and disposed between the axle and the boot holder to bias the boot holder to a central position on the axle. Pin means, parallel to the axle, are mounted to the base plate. The pin means are secured to a locking mechanism and are received in slot means in the boot holder such that the boot holder is pivotally movable to a small extent from a boot holding position when the locking mechanism is in the first position. Control lever means is rotatably and axially mounted on the pin means for controlling the electronic circuit and release of the release member. The control lever has a first lever end engaging the cam surface on the axle and a second lever end operative to engage the boot holder wherein the boot holder engages the second lever end and imparts rotational movement to the control lever when the boot holder moves from the boot holding position. Means are provided for axially moving the control lever along the pin as the soleholder moves along the axle wherein the first lever end moves along the cam surface which imparts rotational movement through the control lever as the soleholder moves from the central position.
In accordance with a preferred aspect of the present invention, the soleholder may be mounted on the horizontal transverse axle with two bushings disposed between the soleholder and the axle. The bushings are preferably stationary on the axle, and reduce the frictional resistance which opposes movement of the soleholder on the axle. Preferably, a helical compression spring is mounted on the transverse axle between the two bushings, and the soleholder is provided with a cylindrical recess having a length equal to the distance by which the bushings are spaced apart. In this respect, the helical compression spring bears at its ends on both the bushing and the soleholder when the spring is in its normal position. Accordingly, as the soleholder is urged laterally from its normal or central position, the helical compression spring will be compressed between one side of the cylindrical recess and one of the bushings. Preferably, the outer ends of the bushings slightly protrude from the soleholder when the soleholder is in its normal position such that the soleholder can axially be displaced from its central or normal position on the transverse axle to either side to a small extent against the biasing force of the compression spring.
In accordance with another aspect of the present invention, the soleholder includes a control lever having first and second lever ends. The second lever end extends downwardly from the horizontal transverse axle and is operatively connected to a foot plate which is movably mounted on the base plate. The foot plate takes up pressure from the ball portion of the skiing boot. In this respect, movement of the foot plate resulting from pressure changes exerted by the ski boot effects the soleholder.
Preferably, the soleholder is mounted on the base portion such that a slight pivotal movement away from the ski boot against the first biasing force is provided. In this respect, the pin means is comprised of a pin which extends through two slots which are formed in lug portions provided on the soleholder. The outer ends of the slots bear on the pin under the action of a compression spring when the soleholder is in its normal position. In this respect, it is desirable to mount the pin such that it is axially movable relative to the base portion but that the soleholder and the control lever are displaceable on the pin in a longitudinal direction along the axis of the ski.
In accordance with the present invention, the soleholder is provided with a recess which serves to receive the control lever and has vertical side surfaces which constitute one way coupling elements associated with the control lever. The control lever as set forth above has two ends, wherein the second end serves as a stop and has a one way coupling element for engagement with the soleholder.
The present invention has heretofore been described as a sensing unit for use with a releasable safety ski binding. In accordance with another aspect of the present invention, the sensing unit heretofore described may also be utilized as part of an automatically releasable jaw unit. In this respect, the sensing unit described above would further include releasable locking means on the base plate for supporting the soleholder. The locking means may comprise a locking member which is adapted to be released by an electromagnet of an electronic circuit. Such releasable locking means may also be used in conjunction with an automatically releasable jaw unit. In this respect, a pin is mounted in a thrust bar which is supported on the base plate for longitudinal movement and is held in a normal position by the locking member. A toggle joint assembly having pivots extending parallel to the transverse axle are provided between the supported ends of the thrust bar and the base plate. In this respect the locking member engages the hinge of the toggle joint from one side thereof and the toggle joint is biased by a return spring. The locking member is preferably comprised of a rotatable element which is mounted on the base plate on a pivot which is parallel to the transverse axle.